Identification of Wnt/ß-catenin modulated genes in the developing retina.

PURPOSE: During mammalian eye development, the restriction of Wnt/ß-catenin signaling at the junction of the neural retina and the retinal pigment epithelium in the peripheral eyecup is required for the development of the ciliary margin, a non-neural region of the eyecup that is the precursor of the ciliary body and iris of the adult eye. METHODS: To identify genes that are modulated by ß-catenin activity in the embryonic retina, we performed gene expression profiling in Li(+)-treated retinal explants, a pharmacological model of ß-catenin activation. The Li(+)-modulated gene data set was searched for ß-catenin/T-cell specific transcription factor binding sites. RESULTS: Functional annotations of this data set revealed significant enrichments for genes involved in chromatin organization, neurogenesis, and cell motion/migration. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis confirmed the modulation of 12 genes in Li(+)-treated explants and retinas of mice with Cre-mediated induction of constitutively active ß-catenin (ß-cat(act)). In situ hybridization revealed ß-catenin-specific upregulation of cyclin-dependent kinase inhibitor 1A (P21) [Cdkn1a] and tumor necrosis factor receptor superfamily, member 19 (Tnfrsf19) in the developing retina consistent with the antineurogenic and proliferation changes associated with ectopic Wnt/ß-catenin signaling in the eyecup. CONCLUSIONS: This data set of Li(+)-modulated genes provides a valuable resource for characterizing the Wnt/ ß-catenin regulated gene network in eyecup patterning.